Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I M5105 #10 Apr 05 2021 11:45:31
%S 20,1071,26320,431739,5494896,58677420,550712668,4681144391,
%T 36786186216,271221867098,1896796135920,12688048319278,81709791432384,
%U 509222462694582,3083998029716868,18213177504318335,105186858991413976,595499805083872458,3311524095424508480
%N Number of rooted toroidal maps with 4 vertices and n faces and no isthmuses.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H T. R. S. Walsh and A. B. Lehman, <a href="http://dx.doi.org/10.1016/0095-8956(75)90050-7">Counting rooted maps by genus. III: Nonseparable maps</a>, J. Combinatorial Theory Ser. B 18 (1975), 222-259.
%Y A diagonal of A343092.
%K nonn
%O 1,1
%A _N. J. A. Sloane_
%E Name clarified and terms a(9) and beyond from _Andrew Howroyd_, Apr 05 2021